In application Ser. No. 231,288, now U.S. Pat. No. 3,815,794 issued June 11, 1974, filed Mar. 3, 1972, it is shown that a pouch can be formed of thermoplastic films edge-sealed together, including a spout constituting a valve that is releasable by internal fluid pressure. Ideally the films are face-to-face adjacent the fused edges. Application Ser. No. 256,850 discloses methods of making many such articles (as well as others) concurrently. Sets of films are stacked, cut out according to the desired shape of the articles, and subjected to fusing heat along the outline where the films are to be edge-sealed together. Each set of films forms one article, each stack thus yielding as many articles as there are sets of films in the stack. Seal-inhibiting material is interposed between each set and the next in the stack so that the articles of the stack are readily separated from each other. Two methods are disclosed in application Ser. No. 256,850. In one method, the films are pre-cut and stacked with their edges aligned or they are cut while stacked, and then the aligned edges are exposed to fusing heat. In the other method, a hot cutter advances along the outline of the articles to be made, making fused seams along the edges of the films of each set in the stack.